Propyl gallate is a superoxide dismutase mimic and protects cultured lens epithelial cells from H2O2 insult
Propyl gallate is a superoxide dismutase mimic and protects cultured lens epithelial cells from H2O2 insult
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DOI：
10.1016/s0014-4835(02)00256-7
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发表时间：
2003-01-01
影响因子：
3.4
通讯作者：
Pena, JT
中科院分区：
文献类型：
--
作者：
Reddan, JR;Giblin, FJ;Pena, JT
没食子酸正丙酯 (nPG) 是一种被美国 FDA 普遍认为安全的食品防腐剂。它抑制生物系统中的氧化。 nPG 在生物系统中的作用机制尚不确定。我们研究了 nPG 是否可以保护培养的晶状体上皮细胞免受 H2O2 诱导的损伤。用H2O2 或用n PG 然后用H2O2 处理细胞。 H2O2 抑制生长，引起膜起泡，减少乳酸产生，增加 GSSG 水平，降低 GSH、ATP 和 NAD(+) 水平以及 G3PDH 活性，刺激单磷酸己糖分流并诱导 DNA 中的单链断裂。 n PG 可防止 H2O2 诱导的生长抑制、膜起泡、NAD(+) 下降和 DNA 中的单链断裂。使用电子顺磁共振 (EPR)、直接分光光度动力学测量和循环伏安法研究了 nPG 在化学水平上的作用机制。当低浓度（nM 至 muM）的 n PG 与大量过量的 O-2(.-) 混合时，超氧化物信号为。紫外可见光谱和 EPR 表明已被破坏。动力学分析表明，在重复添加超氧化物时，n PG 会歧化 O-2(.-)，而活性几乎没有损失。 n PG 与 O-2(.-) 的总反应速率常数约为10(6) M-1 秒(-1)。通过循环伏安法测定，n PG 对 Fe2+ 具有非常低的特异性结合常数。证据表明n PG 以催化方式歧化超氧离子。 (C) 2002 Elsevier Science Ltd. 保留所有权利。
n-Propyl gallate (nPG) is a food preservative that is generally regarded as safe by the US FDA. It suppresses oxidation in biological systems. The mechanism by which nPG acts in biological systems is uncertain. We investigated whether nPG protected cultured lens epithelial cells from H2O2-induced damage. Cells were treated with H2O2 or with n PG and then H2O2. H2O2 inhibited growth, caused membrane blebbing, decreased lactate production, increased the level of GSSG, decreased the levels of GSH, ATP and NAD(+), and G3PDH activity, stimulated the hexose monophosphate shunt and induced single-strand breaks in DNA. n PG prevented the H2O2-induced growth inhibition, membrane blebbing, drop in NAD(+) and single-strand breaks in DNA.The mechanism by which nPG acts at the chemical level was investigated using electron paramagnetic resonance (EPR), direct spectrophotometric kinetic measurements, and cyclic voltammetry. When n PG at low concentrations (nM to muM) was mixed with a large excess of O-2(.-), the superoxide signal was. destroyed as indicated by UV visible spectroscopy and EPR. Kinetic analysis indicated that n PG dismutated O-2(.-) in repetitive additions of superoxide with little loss of activity. The rate constant for the overall reaction of n PG with O-2(.-) was ca. 10(6) M-1 s(-1). n PG had a very low specific binding constant for Fe2+ as determined by cyclic voltammetry. The evidence indicates that n PG dismutates the superoxide ion in a catalytic manner. (C) 2002 Elsevier Science Ltd. All rights reserved.